Sqliz
sqliz.com › mysql › not-null
MySQL NOT NULL
In this article, we will discuss how to use NOT NULL constrain. In MySQL, the NOT NULL is used to constrain a column cannot include a NULL value.
W3Schools
w3schools.com › sql › sql_ref_is_not_null.asp
SQL IS NOT NULL
ADD ADD CONSTRAINT ALL ALTER ALTER COLUMN ALTER TABLE ALTER VIEW AND ANY AS ASC BACKUP DATABASE BETWEEN CASE CHECK COLUMN CONSTRAINT CREATE CREATE DATABASE CREATE INDEX CREATE OR REPLACE VIEW CREATE TABLE CREATE PROCEDURE CREATE UNIQUE INDEX CREATE VIEW DATABASE DEFAULT DELETE DESC DISTINCT DROP DROP COLUMN DROP CONSTRAINT DROP DATABASE DROP DEFAULT DROP INDEX DROP TABLE DROP VIEW EXEC EXISTS FOREIGN KEY FROM FULL OUTER JOIN GROUP BY HAVING IN INDEX INNER JOIN INSERT INTO INSERT INTO SELECT IS NULL IS NOT NULL JOIN LEFT JOIN LIKE LIMIT NOT NOT NULL OR ORDER BY OUTER JOIN PRIMARY KEY PROCEDURE RIGHT JOIN ROWNUM SELECT SELECT DISTINCT SELECT INTO SELECT TOP SET TABLE TOP TRUNCATE TABLE UNION UNION ALL UNIQUE UPDATE VALUES VIEW WHERE MySQL Functions
Videos
02:53
MySQL: NOT NULL constraint - YouTube
04:40
Add not null constraint to existing column in SQL | Mysql tutorial ...
03:24
How to Use Not Null Constraint in MySQL Workbench | MySQL Tutorial ...
MySQL: How To Use Not Null - YouTube
MySQL IS NULL & IS NOT NULL Tutorial in Hindi / Urdu
15:38
Tutorial 3-MYSQL NULL Values, UPDATE,DELETE,ALTER Query-Complete ...
GeeksforGeeks
geeksforgeeks.org › python › adding-a-new-not-null-column-in-mysql-using-python
Adding a new NOT NULL column in MySQL using Python - GeeksforGeeks
July 23, 2025 - Step 2: When you create a NOT NULL column then you can not insert NULL value on that column.
DevGod Blog
devgod.in › blog › 71 › efficient-use-of-mysql-not-null-in-mysql
Efficient Use of MySQL Not Null in MySQL - DevGod Blog
November 16, 2025 - This guide provides an in-depth understanding of the MySQL Not Null query in MySQL.
Techieclues
techieclues.com › tutorials › mysql › mysql-null
MySQL NULL: ISNULL, IS NOT NULL, IFNULL, COALESCE
March 5, 2021 - Below example, the query returns the records when the value for email column is NULL. ... We can get an exactly opposite result here when we use IS NOT NULL, it returns all non-null values.
Dot Net Tutorials
dotnettutorials.net › home › not null constraint in mysql
NOT NULL Constraint in MySQL - Dot Net Tutorials
May 10, 2021 - By default, the database column stores NULL value means no value in the data row. By defining NOT NULL Constraint to the table column, the default behavior of the database column changes and it does not accept NULL values.
TutorialsPoint
tutorialspoint.com › mysql › mysql-is-not-null.htm
MySQL - IS NOT NULL Operator
UPDATE CUSTOMERS SET SALARY = 20000 ... the CUSTOMERS table. In MySQL, we can delete all the non-null rows in a specific column(s) using the DELETE statement with IS NOT NULL operator....
W3Schools
w3schools.com › mysql › mysql_notnull.asp
MySQL NOT NULL Constraint
MySQL Examples MySQL Editor MySQL Quiz MySQL Exercises MySQL Syllabus MySQL Study Plan MySQL Certificate ... By default, a column can hold NULL values. The NOT NULL constraint enforces a column to NOT accept NULL values.
i2tutorials
i2tutorials.com › home › mysql – tutorial › mysql – is not null
MySQL - IS NOT NULL | i2tutorials
February 23, 2023 - Using the MySQL IS NOT NULL condition, we can verify that the expression doesn't contain any NULL values. This statement is used with the SELECT, INSERT, UPDATE, and DELETE statements.
W3Schools
w3schools.com › mysql › mysql_constraints.asp
MySQL Constraints
PRIMARY KEY - A combination of a NOT NULL and UNIQUE.
W3Schools
w3schools.com › sql › func_mysql_ifnull.asp
MySQL IFNULL() Function
ADD ADD CONSTRAINT ALL ALTER ALTER COLUMN ALTER TABLE ALTER VIEW AND ANY AS ASC BACKUP DATABASE BETWEEN CASE CHECK COLUMN CONSTRAINT CREATE CREATE DATABASE CREATE INDEX CREATE OR REPLACE VIEW CREATE TABLE CREATE PROCEDURE CREATE UNIQUE INDEX CREATE VIEW DATABASE DEFAULT DELETE DESC DISTINCT DROP DROP COLUMN DROP CONSTRAINT DROP DATABASE DROP DEFAULT DROP INDEX DROP TABLE DROP VIEW EXEC EXISTS FOREIGN KEY FROM FULL OUTER JOIN GROUP BY HAVING IN INDEX INNER JOIN INSERT INTO INSERT INTO SELECT IS NULL IS NOT NULL JOIN LEFT JOIN LIKE LIMIT NOT NOT NULL OR ORDER BY OUTER JOIN PRIMARY KEY PROCEDURE RIGHT JOIN ROWNUM SELECT SELECT DISTINCT SELECT INTO SELECT TOP SET TABLE TOP TRUNCATE TABLE UNION UNION ALL UNIQUE UPDATE VALUES VIEW WHERE MySQL Functions
W3Schools
w3schools.com › sql › sql_ref_not_null.asp
SQL NOT NULL
ADD ADD CONSTRAINT ALL ALTER ALTER COLUMN ALTER TABLE ALTER VIEW AND ANY AS ASC BACKUP DATABASE BETWEEN CASE CHECK COLUMN CONSTRAINT CREATE CREATE DATABASE CREATE INDEX CREATE OR REPLACE VIEW CREATE TABLE CREATE PROCEDURE CREATE UNIQUE INDEX CREATE VIEW DATABASE DEFAULT DELETE DESC DISTINCT DROP DROP COLUMN DROP CONSTRAINT DROP DATABASE DROP DEFAULT DROP INDEX DROP TABLE DROP VIEW EXEC EXISTS FOREIGN KEY FROM FULL OUTER JOIN GROUP BY HAVING IN INDEX INNER JOIN INSERT INTO INSERT INTO SELECT IS NULL IS NOT NULL JOIN LEFT JOIN LIKE LIMIT NOT NOT NULL OR ORDER BY OUTER JOIN PRIMARY KEY PROCEDURE RIGHT JOIN ROWNUM SELECT SELECT DISTINCT SELECT INTO SELECT TOP SET TABLE TOP TRUNCATE TABLE UNION UNION ALL UNIQUE UPDATE VALUES VIEW WHERE MySQL Functions
MariaDB
mariadb.com › docs › server › reference › sql-structure › operators › comparison-operators › is-not-null
IS NOT NULL | Server | MariaDB Documentation
See also NULL Values in MariaDB. ... SELECT 1 IS NOT NULL, 0 IS NOT NULL, NULL IS NOT NULL; +---------------+---------------+------------------+ | 1 IS NOT NULL | 0 IS NOT NULL | NULL IS NOT NULL | +---------------+---------------+------------------+ | 1 | 1 | 0 | +---------------+---------------+------------------+
IncludeHelp
includehelp.com › mysql › mysql-is-not-null-operator.aspx
MySQL IS NOT NULL Operator
You can simply use this operator with other operators, as you can see the gender column also has null values so we can write a condition that will give us all the values excluding null values from the student department and gender column, in case we will use AND operator between two IS NOT NULL condition.
MySQL Tutorial
mysqltutorial.org › home › mysql basics › mysql not null constraint
MySQL NOT NULL Constraint
January 30, 2024 - Third, modify the column with a NOT NULL constraint. Consider the following example. ... INSERT INTO tasks(title ,start_date, end_date) VALUES('Learn MySQL NOT NULL constraint', '2017-02-01','2017-02-02'), ('Check and update NOT NULL constraint to your database', '2017-02-01',NULL);Code language: SQL (Structured Query Language) (sql)
Top answer 1 of 12
541
You should use IS NOT NULL. (The comparison operators = and <> both give UNKNOWN with NULL on either side of the expression.)
SELECT *
FROM table
WHERE YourColumn IS NOT NULL;
Just for completeness I'll mention that in MySQL you can also negate the null safe equality operator but this is not standard SQL.
SELECT *
FROM table
WHERE NOT (YourColumn <=> NULL);
Edited to reflect comments. It sounds like your table may not be in first normal form in which case changing the structure may make your task easier. A couple of other ways of doing it though...
SELECT val1 AS val
FROM your_table
WHERE val1 IS NOT NULL
UNION ALL
SELECT val2
FROM your_table
WHERE val2 IS NOT NULL
/*And so on for all your columns*/
The disadvantage of the above is that it scans the table multiple times once for each column. That may possibly be avoided by the below but I haven't tested this in MySQL.
SELECT CASE idx
WHEN 1 THEN val1
WHEN 2 THEN val2
END AS val
FROM your_table
/*CROSS JOIN*/
JOIN (SELECT 1 AS idx
UNION ALL
SELECT 2) t
HAVING val IS NOT NULL /*Can reference alias in Having in MySQL*/
2 of 12
25
You can filter out rows that contain a NULL value in a specific column:
SELECT col1, col2, ..., coln
FROM yourtable
WHERE somecolumn IS NOT NULL
If you want to filter out rows that contain a null in any column then try this:
SELECT col1, col2, ..., coln
FROM yourtable
WHERE col1 IS NOT NULL
AND col2 IS NOT NULL
-- ...
AND coln IS NOT NULL
Update: Based on your comments, perhaps you want this?
SELECT * FROM
(
SELECT col1 AS col FROM yourtable
UNION
SELECT col2 AS col FROM yourtable
UNION
-- ...
UNION
SELECT coln AS col FROM yourtable
) T1
WHERE col IS NOT NULL
And I agre with Martin that if you need to do this then you should probably change your database design.
TutorialsPoint
tutorialspoint.com › article › set-not-null-attribute-to-an-existing-column-in-mysql
Set NOT NULL attribute to an existing column in MySQL
December 31, 2019 - Here is the query to set NOT NULL attribute to an existing column − · mysql> alter table DemoTable1949 modify UserName varchar(20) not null; Query OK, 0 rows affected (0.00 sec) Records: 0 Duplicates: 0 Warnings: 0
TutorialsPoint
tutorialspoint.com › article › why-mysql-not-null-shouldn-t-be-added-to-primary-key-field
Why MySQL NOT NULL shouldn't be added to primary key field?
July 30, 2019 - You do not need to add NOT NULL to primary key field because it gets NOT NULL automatically. Primary key is combination of both NOT NULL and Unique Key. Here is the demo of primary key field.
Programiz
programiz.com › sql › is-null-not-null
SQL IS NULL and IS NOT NULL (With Examples)
Here, the SQL query retrieves the count of all the rows from the Employee table where the value of the email column is NULL. ... Similarly, we can use the COUNT() function with IS NOT NULL to count the number of non-empty fields.
Programiz
programiz.com › sql › not-null
SQL NOT NULL Constraint (With Examples)
ALTER TABLE Colleges MODIFY college_id INT NOT NULL; MySQL · ALTER TABLE Colleges MODIFY COLUMN college_id INT NOT NULL; PostgreSQL · ALTER TABLE Colleges ALTER COLUMN college_id SET NOT NULL; Here, the SQL command adds the NOT NULL constraint to the college_id column in the existing Colleges table.